1. Technical Field
The present invention relates to a projector and a control method of a projector.
2. Related Art
Recently, a projection type projector which projects light emitted from a light source on a screen has been widely used. However, a problem in safety that light having high luminance emitted from the projector directly enters a user's eyes is arising. In order to overcome this safety problem, various technologies for protecting the user's eyes from direct entrance of the light emitted from the projector are proposed. According to a projector disclosed in JP-T-11-501419, for example, a sensor detects the possibility that light emitted from the projector is applied to a human. In this case, the projector lowers power of a light source or turns off the switch of the light source. On the other hand, a projector disclosed in JP-A-2004-254145 picks up an image projected on a screen during projection of the image, and compares the obtained image with an input image signal. When it is determined that the user has entered the projection area based on the result of the comparison, the projector decreases the projection light to reduce the glare.
The related-art technologies shown in JP-T-11-501419 and JP-A-2004-254145 eliminate the problem when the user enters the projection area during projection of the image, but cannot cope with the case when the user already exists in the projection area before the start of image projection. For example, when light is emitted by another person's thoughtless operation of a power source under a situation in which the user is at a position where the user directly receives the projection light on the eyes, there is a possibility that the high-luminance and dangerous projection light directly enters the user's eyes. Thus, the safety problem still remains unsolved. Moreover, the related-art technologies which detect the user existing in the projection area by using the sensor or the picked up image or by other methods require a complicated system structure of the projector. In this case, the cost of the system rises.